With recent advancement of storage technologies, the data storage capability of a server has increased as well. Referring to FIG. 1, a conventional server 100 includes a plurality of hard disk drives (e.g., solid state drives, not shown), two storage controller modules (not shown), and a circuit board 101 to which the hard disk drives and the storage controller modules are mounted. The conventional server 100 further includes a plurality of hard disk connectors 102 that are mounted to one side of the circuit board 101, that are electrically connected to the circuit board 101 and that are arranged along a longitudinal direction (L) of the circuit board 101, and a plurality of high speed connectors 103 that are mounted to an opposite side of the circuit board 101, that are electrically connected to the circuit board 101 and that are arranged along the longitudinal direction (L) and adjacent to a bottom side of the circuit board 101. Each of the hard disk drives is electrically connected to a corresponding one of the hard disk connectors 102. The high speed connectors 103 are arranged into two left and right groups that are respectively and electrically connected to the storage controller modules. Each of the high speed connectors 103 is electrically connected to corresponding ones of the hard disk connectors 102 through the circuit board 101 (as shown by the arrows of FIG. 1). Such arrangement requires the circuit board 101 to be formed with multiple staggered layers of interconnects to avoid short circuit among the interconnects. Moreover, such interconnection arrangement may suffer from noise due to interaction among the interconnects. The abovementioned issues are especially prominent in non-volatile memory express (NVMe) interface because there are more than twice the number of the interconnects compared to its precedent, serial attached small computer system interface (SCSI) (abbreviated to SAS).